Certain thiophene-2, 5-diyl-bis (benzoxazole) compounds



United States Patent F of Switzerland No Drawing. Filed Jan. 12, 1965, Ser. No. 425,061

Claims priority, applicatign/Switzerland, Jan. 17, 1964, 3 64 14 Claims. (Cl. 260-307) The present invention provides valuable new 2,5- dibenzoxazolyl-thiophene compounds of the general formula in which X represents a free or neutralized carboxyl group (COO cation) or a functionally converted carboxyl group and Z and Z may be identical or different and each represents a hydrogen atom or a methyl group, and the benzene nuclei may contain further substituents.

Functionally converted carboxyl groups are preferably carboxylic acid ester groups, especially carboxylic acid alkyl ester groups, furthermore alkenyl, aryl or aralkyl ester groups, carboxylic acid halide groups, especially the acid chloride group --COCl, the carboxylic acid nitrile group CN, carboxylic acid amide groups (CONH and amide groups carrying organic substituents on the nitrogen atom).

Particularly valuable 2,5 dibenzoxazolyl thiophene compounds are those of the formula (2) \Z O o z 1 2 on t o s in which X, Z and Z have the above meanings and Y represents a lower alkoxy group. Of special importance in this groups are those compounds in which X has the meaning and position of X in Formula 2 and Y represents a methoxy group.

The new 2,5dibenzoxazolyl-thiophene compounds of-v the above general Formula 1 are obtained by known methods, for example by reacting an ortho-hydroxyaminobenzene, with or without intermediate isolation, at

an elevated temperature and if desired or required in the presence of a catalyst, at the molecular ratio of 2:1 with a dicarboxylic acid of the formula (3) Z1CCZz H noon-( i o-ooon in which Z and Z may be identical or different and each represents a hydrogen atom or a methyl group, or with a functional derivative of this dicarboxylic acid, using an ortho-hydroxyaminobenzene of the formula 4 NHz in which X represents a functionally converted carboxyl group, preferably a carboxylic acid ester group. This ortho-hydroxyaminobenzene may contain with advantage an additional alkoxy group, in ortho-position to the hydroxyl group, more especially a methoxy group. If desired, the functionally converted carboxyl groups in the products obtained in this manner may be hydrolyzed or converted into other functionally modified carboxyl groups.

Particularly suitable starting materials are, for example, orthohydroxyaminobenzenes of the formula 5 NHz in which X represents a carboxylic acid alkyl ester group, for example a carboxylic acid-methyl, -ethyl, npropyl, isopropyl, n-butyl, 2-ethylhexyl or methoxyethyl group. Orthohydroxyaminobenzenes of this kind are known or can be obtained by known methods.

The further used starting material is a dicarboxylic acid of the Formula 3, for example thiophene-2,5dicarboxylic acid, 3,4 dimethyl-thiophene 2,5-dicarboxylic acid or.monomethyl-thiophene-2,5-dicarboxylic acid, or a functional derivative of one of these dicarboxylic acids,

preferably a dicarboxylic acid dichloride.

The reaction of the selected reactants can be performed with or without intermediate isolation by heating at an elevated temperature, for example from to 320 C., advantageously in an inert gas, for example under nitrogen, and if required or desired, the reaction may be conducted in.the presence of a catalyst. Suitable catalysts are, for example, boric acid, zinc chloride, para-toluenesulfonic acid, also poly-phosphoric acids including pyrophosphoric acid. When boric acid is used as catalyst, it is advantageously used in an amount of about 0.5 to 5% preferred to the total weight of the reaction mass. There may further be used as condensing medium high-boiling, polar organic solvents, for example dimethylformamide or aliphatic (if desired etherified) hydroxy compounds, for example dialkylcarbitols, propyleneglycol, ethyleneglycol monoethyl ether or diethyleneglycol diethyl ether and high-boiling esters of phthalic acid, for example phthalic acid dibutyl ester.

Alternatively, the reaction may be performed in two stages by first condensing 1 mol of a dicarboxylic acid of the Formula 3 or of a functional derivative thereof, especially a dicarboxylic acid dichloride, with 2 mols of ortho-hydroxyaminobenzene in the presence of an organic solvent such as toluene, a xylene, chlorobenzene, dichlorobenzene or nitrobenzene at an elevated temperature, whereupon the resulting acyl compound is converted into the dibenzoxazole at an elevated temperature, if desired or required in the presence of a catalyst. boxylic acid dichloride is used as starting material, it may be prepared immediately prior to the condensation with the ortho-hydroxyaminobenzene and without isolation from the free dicarboxylic acids and thionylchlon'de in the same solvent in which the condensation is subsequently carried out.

Patented June 7, 1966 When a dicar- 3 The 2,S-dibenzoaxolyl-thiophene compounds of the formula R O O C -NH (R =alkyl) whereupon the resulting acylamino compound of the formula (R =alkyl) is converted, without using a catalyst or in the presence of boric acid and in an organic solvent at an elevated temperature, into the dibenzoxazole compound of the formula and, if desired, the carboxylic acid alkyl ester groups are hydrolyzed in the known manner. The conversion of free carboxyl groups into neutralized carboxyl groups (ammonium, metal or amine salts) or into functionally modified carboxyl groups is likewise achieved by known methods. Thus, for example, nitrile groups can be hydrolyzed, and/r free carboxyl groups esterified with organic hydroxy compounds (alcohols or phenols) or converted with, for example, thionylchloride into carboxylic acid chloride groups which are then converted into carboxylic acid amide groups by reaction with ammonia or with a primary or secondary amine.

In the form of solutions or fine dispersions the .new thiophene derivatives of the composition defined above display a more or less pronounced fluorescence. They may be used for optically brightening a wide variety of materials, especially organic materials. Good results are obtained, for example, in brightening acrylic resin lacquers, alkyd resin lacquers, cellulose ester lacquers, for example acetylcellulose lacquers, or nitrocellulose ester lacquers. The new thiophene derivatives are particularly suitable for optical brightening synthetic fibres, for example fibres from cellulose esters such as cellulose propionate or acetylcellulose (cellulose diacetate or cellulose triacet-ate; acetate rayon), more especially fibres from polyamides (e.g., nylon) or polyesters (e.g., Dacron, terylene), polyurethanes, or from polyolefines such as polyethylene or polypropylene, from polyvinylchloride or polyvinylidenechloride, and also films, foils, tapes or mouldings from these materials or other materials such as polystyrene and its copolymers, for example, with unsaturated polyesters, polyvinyl alcohol or polyvinyl esters of organic acids, for example, polyvinyl acetate, or copolymers of organic vinyl esters with other copolymerizable monomers.

If the present process is to be used for optically brightening synthetic fibreswhich may be in the form of staple fibres or filaments, in the crude state or in the form of "hanks or woven fabricsit is advantageously carried out in an aqueous medium in which the compounds concerned are suspended. If desired, the treating liquors may further contain a dispersant, for example, soaps, polyglycol ethers of fatty alcohols, fatty amines or alkylphenols, cellulose sulphite waste liquor or condensation products of formaldehyde with (possibly alkylated) naphthalenesulfonic acids. It has been found to be especially advantageous to work in a neutral, weakly alkaline or acid bath. Likewise, it is advantageous to perform the treatment at an elevated temperature from about 50 to 100 C., for example at the boiling temperature of the bath or near it (at about C.). The improvement according to this invention can also be achieved with solutions in organic solvents.

The new thiophene derivatives to be used in the present process may also be added to, or incorporated with, the materials before or during their shaping. Thus, they may be added to the moulding compositions used for the manufacture of films, foils, tapes or shaped articles, or they may be dissolved or finely dispersed in the spinning mass before spinning. The new brighteners may also be added to the reaction mixtures before or during the polycondensation leading, for example, to polyamides 0r polyesters, or before or during the polymerization or monomers, for example vinyl acetate, to the polymerization masses.

The proportion of the new thiophene derivatives to be used, referred to the weight of the materialto be optically brightened, may vary within wide limits. Even a very small amount, in certain cases for instance as little as 0.01%, may produce a distinct and durable effect. It is however, also possible to use an amount of up to about 0.5% or more.

The new thiophene derivatives may be used as bright eners also as follows:

(a) In admixture with dyestuffs or pigments or as additives to dyebaths, or printing, discharge or resist pastes. Furthermore also for after-treating dyeings, prints or discharge effects.

(b) In admixture with chemical bleaches or as additives to bleaching baths. 4

(b) In admixture with dressing agents such as starch or synthetic dressings. The products of this invention may also be used for example, to produce a creaseresistant finish by adding them to the liquors used for this purpose.

(d) In combination with detergents, the detergents and brighteners may be added to the washing liquors separately. It is also of advantage to use detergents that as such contain the brightener. Suitable detergents are, for example, soaps, salts of sulfonate detergents, for example of snlfonated benzimidazoles substituted on the 2-carbon atom by higher alkyl radicals; also salts of monocarboxylic acid esters of the 4-sulphophthalic acid with higher fatty alcohols: also salts of fatty alcohol sulfonates, alkylarylsulfonic acids or condensation products of higher fatty acids with aliphatic hydroxysulfonic or aminosulfonic acids. Furthermore, there may be used nonionic detergents, for example polyglycol ethers derived from ethylene oxide and higher fatty alcohols, alkylphenols or fatty amines.

If the present process is combined with other treatment or improving operations, the combined treatment is advantageously carried out with the aid of suitable preparations. These stable preparations contain compounds of the above Formula 1 as well as dispersants, detergents,

. dyestuffs, pigments or dressing agents.

The compounds of the above Formula 1 may also be used after having been fixed on a finely dispersed vehicle. The brightening effects that can be achieved with the compounds of the Formula 1 are very valuable. More 3,255,199 6 particularly, brightening effects on polyamide fibres and allowed to cool. polyesters aredistinguished by their neutral white, good Yield: about 320 parts of the compound of the formula fastness to light and good thermostability or, respectively,

0 N 1 N o stability towards migration. II HG CH II Unless otherwise indicated, parts and percentages in H3GO*C II [I the following examples are by weight. 7

as a beige-colored powder melting at 280 to 283 C.

A mixture of 172 parts of thiophene-2 S-dicarboxylic,

10 The analytically pure product, obtained by recrystallizaacld 1600 parts by volume of ortho'dlchlorobenzene 300 tion from dimeth lformamide and sublimation in a hi h parts by volume of thionylchloride and 2 parts by volume vacuum, malts at to of pyridine is stirred for 12 hours at 85 to 90 C. Hydro- C22H14O6N 5 calculated. C 6033. H 3 N 6 45% chloric acid gas escapes and a clear, yellowish solution Found C H 32'1 6 1 forms. The excess thionylchloride is then suctioned off 43 4 a under vacuum and the solution of the acid chloride in dichlorobenzene is cooled to 50 C. 334 parts of 3- amino-4-hydroxybenzoic acid methyl ester are added, whereupon a suspension forms which is heated within (12) H N N about 2 hours to 175 to 180 C.; at about 140 C. a strong H@C0-0 f f .O0OH evolution of hydrochloric acid sets in. After another 5 0-0 0-0 to 6 hours the evolution of hydrochloric acid ceases.

The yellow, pasty suspension is cooled to room tempera- I o o ture, suctioned and the filter cake is rinsed with dichloro H30 0 OCH; benzene, suspfinded in 3000 Parts y Volume methanol Light' beige-colored, crystalline powder from dimethyland heated for a short time at the boil, then suctioned at formamide, melting at 273' to 276 C.

Example 1 The following dibenzoxazolyl-thiophene compounds can be made in an analogous manner:

room temperature and thoroughly rinsed with methanol. C H Q N S calculated: C, 58.30; H, 3.67; N, 5.67%. After drying, there are obtained about 413 parts of the Found; C, 5 H, 3.76; N, 5.61%. MOL weight; compound of the formula 494 4 0 NH EN 0 N N II HCCH C g H(I% (IJIH C-OCH3 O II 0 C-0 C0 H C-C\ /CC H ll t! H3CCH20-C 0 C-0CH2CH HO 3:) 0 0 Light yellow, finely crystalline powder from dimethylas a beige-colored powder melting at 316 to 318 C. formamide, melting at 243 to 244 C.

503 parts of the compound of the Formula 10 are C H O N S calculated: C, 62.33; H, 3.92; N, 6.06%.

stirred under nitrogen with 5 parts of boric acid in 1000 Found: C, 62.46; H, 3.92;. N, 6.02%. M01. weight: parts by volume of dibutylcarbitol. The reaction mixture 462.49.

II [I moomomomo-oi C-OOHzCHzCHrCHa -o oo is then heated within 4 hours to 245 to 250 C., with the Yellowish, felted flakes from toluene-l-cyclohexane, meltsolvent beginning to pass over. The temperature is maining at 189 to 190 C.

tained for 2 to 3 hours between 250 and 260 C., and C H O N S calculated: C, 64.85; H, 5.05; N, 5.40%. there are obtained about 700 parts by volume of an aque Found: C, 64.99; H, 5.02; N, 5.45%. M01. weight: ous distillate and as a residue a turbid melt diluted with 518.59.

solvent. The melt is diluted with dimethylformamide Light beige-colored, finely crystalline powder from diwhile still hot, then allowed to cool, suctioned and the methylforrnamide, melting at 205 C.

filter cake is rinsed with dimethylformamide. C H O N S calculated: C, 65.92; H, 5.53; N, 5.12%.

The residue is dissolved in much hot dimethylform- Found: C, 66.07; H, 5.43; N, 5.36%. M01. weight: amide, the undissolved matter is filtered off and the filtrate 546.64.

(16) moon H N N I omen. moornomcmonomo-of 6 h-oo112oHoHt0H2oH2oH,

7 8 Yellowish flakes from cyclohexane, melting at 121 to tion mixture is suctioned at room temperature (about 20 122 C. C.) and the residue is washed neutral with water. After C H O N S calculated: C 68.55, H 6.71, N 4.44%. drying, there are obtained about 57.5 parts of the dicar- Found: C 68.31, H 6.80, N 4.33%. M01. weight: 630.80. boxylic acid of the formula Yellow, crystalline powder from benzene, melting at 185.5 (20) N N to 186 C. H HC OH C H O N S calculated: 0 59.76, H 4.24, N 5.36%. g ll Found: C 59.92, H4.15, N 5.39%. M01. weight: 522.53.

.Example 2 S 0 A mixture of 11 Parts of the dicarboxylic acid ester 0f as a dark-beige colored powder which does not melt below the Formula 250 Parts by Volume of Q Q g0 350 C. On crystallization from dimethylformamide, a benzene and 40 parts by volume of n-octylamine is kept yeuow beige powder is obtained which does not melt for 72 hours under a slight reflux, whereupon a clear solubelow 3 c tion is obtained which is allowed to cool to room tempera- CzOHwOGNZS calculated; C 59.11, H 248 N 6'39% ture (abo t and the precipitate formed is SW Found: c 59.01, H 2.56, N 7.14%. M01. weight: 406.37. tioned off and washed with methanol. After drying, there are obtained about 10 parts of a light-yellow powder melt- Example 4 8 at 261 Repfiated recrystallization from 57.4 parts of finely powdered dicarboxylic acid of the dimethylformamide furnishes the diamide of the formula Formula 20 are suspended in 400 parts by volume of as a P Y Crystalline P melting at 292 to anhydrous chlorobenzene. 7.5 parts by volume of thionyl- 293 C. chloride and 5 drops of dimethylformamide are added and C H O N S Cal ulat d! C H 7.05, N 8.91%- the whole is stirred for 6 hours at 90 to 95 C.; the evolu- Found: C 68.67, H 6.97, N 9.10%. M01. Weight: 628.84. tion of hydrochloric acid then ceases and a thick, yellow suspension is obtained. It is suctioned at room temperature (about 20 C.) and the filter cake is washed with mlXtllfe 0f Parts of finely powdelied dlcarboxyhc anhydrous hexane. After drying, there are obtained about a ld s r 0f the Formula 11 and a sollltlon 0f 54 Parts 56 parts of the dicarboxylic acid chloride of the formula of sodium hydroxide in 150 parts by volume of water and Example 3 1,200 parts by volume of ethyleneglycol monomethyl ether N 1 N is refluxed for 24 hours, then allowed to cool to room g H temperature (about 20 C.), and the residue is suctioned B off and thoroughly rinsed with methanol. To remove any residual starting material from the residue it is boiled O S O with 2000 parts by volume of ortho-dichlorobenzene. as a yellow powder melting at 260 to C After drying, there are obtained about 75.3 parts of the disodium salt of the formula Example 5 4.1 parts of the dicarboxylic acid chloride of the Foru mula 21 are suspended in 100 parts by volume of anhy- NaO-C i 1 drous chlorobenzene. 5 parts of 4-(l,1',3',3-tetramethylbutyl)-phenol and 5 parts by volume of pyridine are added S and the whole is refluxed for 2 hours, to form a turbid 0 0 solution, which is mixed with 150 parts by volume of ethanol and allowed to cool to room temperature (about as a beige-colored, granular powder which does not melt 20 C.). The batch is suction-filtered and the pale-yellow below 350 C. residue washed with alcohol. Two recrystallizations from The disodium salt of the Formula 19 is finely powdered toluene with the aid of active carbon yield the compound and suspended in 4000 parts of boiling water. In the of the formula course of 30 minutes dilute hydrochloric acid is added as a pale-yellow, crystalline powder melting at 251 to drop by drop until a strongly acid reaction to Congo red 252 C.

has been attained, and the batch is refluxed for another 30 C H O N S calculated: C 73.63, H 6.44, N 3.58%. minutes and then allowed to cool with stirring. The reac- Found: C 73.81, H 6.33, N 3.64%. M01. weight: 783.00.

9 10 The following dibenzoxazolyl-thiophene compounds can efiect which is stable to thermosetting and has good fastbe made in an analogous manner: mess to washing and light.

Light-yellow, small needles from toluene, melting at 229 Example 8 to 230 C. A melt prepared from 100 parts of polyester (poly- C34H22O6N2S calculatfid! C 69-61, H N terephthalic acid ethyleneglycol ester) and 0.05 part of Found: C 69.71, H 3.90, N 4.77%. M01. weight: 586.62. the compound of the Formula 11 is expressed through C s O O Light-yellow, crystalline powder from. dimethylformamide, a nozzle to form a tape. The polytster tape produced in melting at 200 to 202 C. this manner has a substantially higher white content than C H O N S calculated: C 64.19, H 3.73, N 5.76%. a tape that does not contain the thiophene compound.

Found: C 64.22, H 3.72, N 6.02%. M01. weight: 486.50. What is claimed is:

() H N N I? Ha H2)11OC j fi 00( 2 11crn Faintly yellowish, finely crystalline powder from tolu- 1. A 2,'5dibenzoxazolyl-thiophene compound of the ene, melting at 145 to 146 C. formula C H O N S Calculated: C 73.80, H 9.07, N 3.07%.

H Example 6 X N N r C Found C 73 62, H 8 97, N 2 95% M01 wel ht 911 34 35 \Zl 21% G-C X I 6 parts of the dicarboxylic acid chloride of the Formula S 21 are dissolved in 250 parts by volume of anhydrous chlorobenzene by heating to the reflux temperature. 10 parts of ethanolamine are then added dropwise, wherewherein X represents a member selected from the group upon a light-yellow precipitate is immediately formed. consisting of a COOH group, a COO cation, 21 The batch is refluxed for 10 minutes longer, suctioned at car-boxylic alkyl ester group, said alkyl group containing room temperature, and the residue is washed with alcohol. from 1 to 20 carbon atoms, a carboxylic alkylphenyl On dissolution in d-imethylsulfoxide, clarifying by filtraester group containing 1 to 20 carbon atoms in the alkyltion and precipitation with alcohol there are obtained phenyl group, a carboxylic phenylalkyl ester group conabout 5.5 parts of the compound of the formula taining 1 to 20 carbon atoms in the phenylalkyl group,

(26) N I N HOHzCCH2NH-( i HCCH CNHCH:CH=OH as a light-beige colored, finely crystalline powder which a canboxylic acid allyl ester group, a carboxylic halide does not melt below 350 C. Crystallization from digroup, a carboxylic acid nitrile group, a carboxylic acid methylformarnide furnishes pale-yellowish flakes which amide group CONH and a carboxylic acid amide group do notmelt below 350 C. -CON-HR", wherein R" represents a member selected C H O N S calculated: C 58.53, H 4.09, N 11.38%. from the group consisting of an alkyl radical and a hy- Found: C 5 8.80, H 4.23, N 11.39% Mol weight: 492.51. droxyalkyl radical, each of which contains 1 to 20 carbon atoms, Z and Z each represents a member selected from the group consisting of a hydrogen atom and a methyl 10, Parts f a Polyamide in p i01m, P p group and Y represents a member selected from the in the known manner from hexamethylenediamine adipate, group consisting of hydrogen and a methoxy group. are mixed for 12 hours in a tumbler with 30 parts of 2, Acompound of th f ula titanium dioxide (rutile modification) and '10 parts of Example 7 the compound of the Formula 11. The chips treated in N Y N this manner are melted in a boiler which is heated at 300 X fif H Xa to 310 C. with oil or diphenyl vapour and from which c the atmospheric oxygen has been displaced with superheated steam, and the melt is stirred for half an hour, 0 0

and then expressed through a spinneret under a nitrogen pressure of 5 atmospheres (gauge). The resulting, cooled wherein X represents the carboxylic ester group COOR' filament is wound on a spinning bobbin. The filaments wherein R stands for an alkyl radical of from 1 to 20 obtained in this manner display an excellent brightening carbon atoms.

3. A compound of the formula wherein X represents the carboxylic ester group COOR wherein R stands for an alkyl phenyl radical of from 1 N N X HC-CH to 20 carbon atoms.

2 a 6. A compound of the formula s HC---CH 0 wherein X represents a canboxylic acid amide group CONHR" wherein R stands .for an alkyl radical of s from 1 to 20 carbon atoms.

4. A compound of the formula 10 wherein X represents the carboxylic ester group COOR' wherein R stands for a phenylalkyl radical of from 1 N N X HO-CH X to 20 carbon atoms.

' 54 a 7. The compound of the formula H000 \CHZEC/ c0011 wherein X represents a carboxylic acid amide group CONHR" which R" stands for a hydroxyalkyl radical r s 0 of from 1 to carbon atoms 20 8. The compound of the formula 5. Acompound of the formula N N I HC-CH FI COOCH: X1 \C g C C/ X1 /o-c o-o\ \O s 0 S O 9. The compound of the formula 10. The compound of the formula 11. The compound of the formula 13. The compound of the formula (References on following page) References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Ny-ilas et al., J. Am. Chem. Soc., vol. 82, pages 609-611 Hein et a1. 260-3074 (1960)- Ackermann et a1. 252-301.2 Liechti et aL 260 3O7 5 HENRY R. JILES, Acting Przmary Examzner. Maeder et a1. 260-307 A. D. ROLLINS, Assistant Examiner.

Tan] et a1. 252301.2 

1. A 2,5-DIBENZOAXAZOLYL-THIOPHENE COMPOUND OF THE FORMULA 